Determine the antitumor effect of the radiolabeled murine monoclonal antibody 131I-CC49 in patients with metastatic colorectal cancer, determine the toxicity of 131I-CC49, determine whether administration of IL-1B reduces the myelosuppression produced by 131I-CC49, determine the toxicity of IL-1B, and determine the effect of IL-1B on circulating hematopoietic stem cells.